1. People in the Song Dynasty could eat spinach when eating hot pot. In ancient times, potatoes were introduced in the late Ming Dynasty, while spinach was introduced in the Zhenguan period of the Tang Dynasty. The Song Dynasty was later than the Tang Dynasty and earlier than the Ming Dynasty, so people in the Song Dynasty could eat spinach.

2. The types of vegetables eaten by the ancients have gone through a process of changing from a small amount to a large amount. The Qin and Han Dynasties made it possible. There are five main types of vegetables eaten by the Chinese people: sunflower, hyacinth, scallions, green onions, and leeks. Zhenguan of the Tang Dynasty Spinach was introduced from Nepal during the 19th century, and potatoes were introduced in the late Ming Dynasty.

3. Potatoes crossed the ocean and were introduced to China in the late Ming Dynasty. Xu Wei, a literati from the Wanli Dynasty, wrote a five-rhythm poem "Potato": "Hazelnuts are not soft enough, and wild rice roots are destined to be female." Flowers are falling from the sand of Wu, and the owl is squatting on the leaves of the Shu Kingdom. There is still no one to drink tea, and the person is still shy and knows how to appreciate it. To regard it as a delicacy is enough to show that potatoes were still a rare thing during the Wanli period.

4. Corn, originally from Mexico, America, was introduced to China in the 16th century. Due to its high yield, resistance to barrenness, and cold resistance, some remote and cold mountainous areas and marginal lands were developed and utilized, expanding the scope of China's agricultural production. The geographical space and time configuration promote the rapid development of agriculture.